The present invention relates to a presetting counter device in which the counter setting is successively reduced by a repeated operation, for example, such that a dial set for the desired number of operation cycles is turned for every cycle and returned toward its reference position.
Devices of this type are widely used in copying machines. As shown in FIG. 1 for example, such devices comprise a cycle repeating control drum D coupled to a copy number setting dial (not shown) and fixedly provided with a ratchet wheel A for reducing the setting of the dial, a toothed wheel B having round teeth and providing a click stop at each position to which the ratchet wheel A is indexed, and a cam C having a recess c in its outer periphery. The elastic engagement of a bent portion e of a leaf spring E with the toothed wheel B produces a click at each indexed position of the ratchet wheel. A counter pawl lever F having an actuating pawl f detachably engageable with the ratchet wheel A has a rear end pivotally connected by a pin I to an upper end portion of a counter actuating lever H pivotally connected in place at its rear end by a pin G. The pawl lever F has at its front end a cam portion J resting on a rod K. A spring L acting between the levers F and H biases the pawl lever F in a direction to bring the cam portion J into pressing contact with the rod K and to bias the pawl f toward engagement with the ratchet wheel A. The cam portion J has a first restraining face j.sub.1 at the front end of the lever F for retaining the lever F in a position where the pawl f is in engagement with the ratchet wheel A, and a second restraining face j.sub.2 extending from a slanting face j.sub.3 continuous with the face j.sub.1. The second restraining face j.sub.2 is adapted to bear against the rod K to hold the pawl lever F in a position shown in FIG. 1 in which the pawl f is out of engagement with the ratchet wheel A.
The actuating lever H is biased by a spring M to urge the pawl lever F toward its front end, usually positioning the second restraining face j.sub.2 in pressing contact with the rod K. The contact of a stopper face j.sub.4 at the rear end of the second restraining face j.sub.2 with the rod K holds the pawl lever F in this position with stability. A driven lever P pivotally connected by a pin Q to the upper end of the actuating lever H is adapted to be acted on by a one-way engaging lever O secured to a document carriage N. The carriage N performs a stroke of reciprocal movement for each copying cycle. A spring R retains the driven lever P in contact with a lug h at the upper end of the actuating lever H. Thus the lever P is held in position as an upper end extension of the actuating lever H and is movable with the lever H under the action of the spring R. The one-way engaging lever O is made of elastic material such as synthetic resin and comprises a base piece o.sub.1 attached to the document carriage N and a lever piece o.sub.3 connected to the base piece o.sub.1 by a thin hinge portion o.sub.2. Lever P lies in the path of downwardly extending lever piece o.sub.3, so that lever piece o.sub.3 kicks the lever P when the document carriage N travels in a direction S, for example, during a return movement. And, the lever piece o.sub.3 tilts about the hinge portion o.sub.2 away from the lever P when the carriage N travels in the opposite direction.
A reference position detecting lever T, pivotally mounted at its one end on the rod K, is biased by a spring U to cause a projection t thereon to bear against the cam C (as shown in FIG. 1), and has the other end thereof connected by a pin W to a member V vertically movable over a specified distance as determined by the elongated slots in member V in engagement with stop pins (not referenced) mounted in place. A cycle repeating lever Y pivotally connected by a pin X to the upper end of the vertically movable member V has an upwardly projecting driven piece y.sub.1 adapted to be acted on by a cycle repeating signal member RS attached to the carriage N. The lever Y further has a cam portion y.sub.2 for actuating a switch SW for emitting a cycle repeating signal. The lever Y is so biased by a spring Z that the driven piece y.sub.1 is in its upwardly raised position at all times. The one-way engaging lever O opposes the driven lever P at a position different from the position where the signal member RS opposes the cycle repeating lever Y to avoid interference between the opposed pairs.
The illustrated device is in position for making a single copy. The unillustrated copy number setting dial is set in its reference position for making one copy, and the control drum D is also in its reference position. The projection t on the reference position detecting lever T is held in the recess c of the cam C by the action of the spring U. The lever T has been turned counter-clockwise in FIG. 1, holding the vertically movable member V in its lowered position. Accordingly the cycle repeating lever Y is also in its lowered position with its driven piece y.sub.1 retracted from the path of travel of the cycle repeating signal member RS. Even when the document carriage N travels, the member RS does not push the lever Y to cause the lever Y to actuate the switch SW. With no repeating signal emitted from the switch SW, the copying operation is terminated upon completion of the single copying cycle.
The pawl of the pawl lever F opposes the toothless portion a of the ratchet wheel A. When the document carriage N returns, the lever piece o.sub.3 of the one-way engaging lever O kicks the driven lever P, causing the actuating lever H to move the pawl lever F leftward. With the leftward movement of the lever F, the portion of the lever F in contact with the rod K shifts from the second restraining face j.sub.2 to the slanting face j.sub.3 and then to the first restraining face j.sub.1, rendering the pawl f engageable with the ratchet wheel A. However, the leftward movement brings the pawl f into sliding contact with the toothless portion a without rotating the control drum D. Consequently the copy number setting dial remains in the position of single copy setting.
When the counter device is to be set for more than one copy, the control drum D is turned by the setting dial in the direction of arrow S.sub.1 by an amount corresponding to the number of copies, n, bringing the ratchet wheel A to a position in which the (n-1)th tooth thereof from the toothless portion a is opposed to the pawl f. Similarly the recessed portion c of the cam C is turned through the same angle, pushing out the projection t on the detecting lever T from the recess c onto the outer periphery of the cam C and thereby turning the lever T clockwise in FIG. 1. This movement causes the lever T to raise the vertically movable member V, consequently positioning the driven piece y.sub.1 of the lever Y in the path of travel of the signal member RS.
The movement of the document carriage N in this state causes the member RS to kick the driven piece y.sub.1. When the driven piece y.sub.1 is kicked during the forward travel of the carriage N, the actuating lever Y turns clockwise in FIG. 1 without permitting the cam portion y.sub.2 to act on the switch SW, whereas only when the lever Y is turned counterclockwise by the pushing contact of the member RS with the driven piece y.sub.1 during the return of the carriage N, the cam portion y.sub.2 actuates the switch SW, which in turn emits a signal for the repetition of the cycle. During the return of the carriage N, the lever piece o.sub.3 also kicks the driven lever P, moving the pawl lever F leftward as aforedescribed. With this movement, the pawl f comes into engagement with the tooth opposed thereto of the ratchet wheel A and rotates the control drum D in the direction of arrow S.sub.2 by an amount corresponding to the pitch of the wheel A. This reduces the setting of the dial by one. Thus the number of copies set on the counter is cyclically reduced in succession. With the setting reduced to one, the device is restored to the illustrated position to terminate the copying operation.
With the conventional device described above, one control drum is used for the reduction of the setting and the attendant return of the cycle number setting dial as well as for the repetition and termination of the operation cycle. The device further includes two lever mechanisms for reducing the setting (and returning the setting dial) and for controlling the repetition of operation cycle, respectively. The device incorporating these components within a small limited space is difficult to design, necessitates a complex arrangement of levers, is complex in construction and requires a cumbersome assembling procedure. Such a device is therefore liable to malfunctions and is costly to manufacture.